Well the King of Prussia had rights as souvereign of the cantonate of Neuenburg, leading to a royalist revolt in 1848 when the liberals rebelled against the administration.
switzerland had a "civil war" in 1847, when the conservative- ultramontane rural cantons formed the "Sonderbund" (special alliance) but where beaten by the liberal, more powerful city cantons.
But one element of stress in Switzerland was the oppression of the rural areas which were ruled by the cities like Genf, Zürich, Bern, Basel.
These cities themselves were ruled by a city principate until the french marched in and later proclaimed the helvetian republic.
So: IN order to preserve their hegemony, the city magnates invite some mediated ruler to take over as king, not neccessary like with this title, something like the Oranians in the United provinces of the Netherlands in the 16th/17th century.